In this paper we investigate the relation between lateral cross-bite disorders and the sounds generated by the Temporomandibular Joint (TMJ). TMJ vibrations are recorded clinically by palpation and auscultation and also electronically by accelerometers. TMJ signals are filtered amplified digitized and stored on a computer. Based on joint time-frequency moments calculated from evolutionary spectrum,sounds are categorized into four classes. Palpation, auscultation, and time-frequency classification findings are presented.